Comparison of Early Outcomes in Patients at Estimated Low, Intermediate and High Risk Undergoing Transcatheter Aortic Valve Implantation: A Multicentre Australian Experience

Background: Transcatheter aortic valve implantation (TAVI) has been shown to be a safe and effective alternative to surgical aortic valve replacement (SAVR) in high- and intermediate-risk patients with severe aortic stenosis. TAVI for patients at lower risk of periprocedural mortality has not been extensively investigated. We aimed to describe outcomes in low-, intermediate- and high-risk patients undergoing TAVI in a multicentre Australian study.

Methods: We evaluated data from 601 patients who underwent TAVI at two hospitals in Melbourne, from August 2008 to February 2018. Patients were stratified according to low risk (STS <4%), intermediate risk (Society for Thoracic Surgeons [STS] 4.0-7.9%) and high risk (STS >8%). Outcomes were reported according to Valve Academic Research Consortium-2 (VARC-2) criteria.

Results: Mean age was 84±5 years and 49% were female. Two hundred and eighty-five (285) (47%) patients were low-risk, 243 (40%) were intermediate risk and 73 (12%) were high risk. Thirty-day (30-) mortality was low in all three groups (1.1%, 1.7% and 1.4%, respectively, p=0.8). Similarly, patients had a low risk of disabling stroke (0.4%, 1.3%, 0%, p=0.8). Rates of post-procedural permanent pacemaker were also similar (21%, 27%, 26%, p=0.5). At least moderate aortic regurgitation occurred in 9% of patients at discharge with no significant differences between groups.

Conclusions: In this large Australian multicentre cohort of TAVI patients, 30-day mortality, and post-procedural outcomes were excellent and similar across the patient-risk spectrum. Our study offers further support for the safety of TAVI in low-risk populations and demonstrates the limitations of the STS score.